Many food processing operations require adding a processing fluid or other material to a foodstuff. The traditional method for adding materials to a foodstuff comprises placing the foodstuff together with the material to be added in a suitable mixing vessel and then mixing the two materials together. This mixing process is well adapted for many applications, but may over-work the foodstuff and produce undesirable results in some cases.
U.S. Pat. No. 5,871,795 discloses an apparatus and process for adding pH modifying materials to foodstuffs, particularly comminuted meats. The system disclosed in U.S. Pat. No. 5,871,795 applies the pH increasing or pH decreasing material in gaseous form. Ammonia gas is given as a specific example of a pH increasing gas useful in the system, while carbon dioxide gas is listed as an example of a pH decreasing gas that may used in the system. Modifying the pH of the foodstuff in the process described in U.S. Pat. No. 5,871,795 has been shown to reduce microbe counts in the foodstuff and may have other benefits in processing the foodstuff.
U.S. Pat. No. 6,142,067 discloses a system for adding ammonia to finely comminuted meats. In this apparatus, the comminuted meat is pumped through a narrow conduit, a portion of which passes adjacent to a chamber containing the ammonia. A number of small openings extend from the ammonia chamber to the interior of the conduit and provide fluid communication from the ammonia chamber to the conduit. This arrangement of a meat conduit, ammonia chamber, and openings from the chamber to the conduit may be referred to as a sparger or sparging device. The pressure is regulated in the ammonia chamber to cause the desired amount of ammonia to be “sparged” into the foodstuff, that is, to flow through the small fluid communication openings into the meat conduit and make contact with the meat product.
In the system shown in U.S. Pat. No. 6,142,067 the meat product and added ammonia is directed through a grinder or other similar device. Grinding or otherwise further comminuting the foodstuff after addition of ammonia operates to evenly distribute the ammonia throughout the comminuted meat. This system of adding ammonia to comminuted meat and then further comminuting the meat has been shown to provide a substantially even pH increase throughout the comminuted meat and allows significant pH increases without leaving the meat with an ammonia odor.
The systems shown in U.S. Pat. Nos. 5,871,795 and 6,142,067 work well for adding a processing fluid to a foodstuff, especially comminuted meats. However, it is desirable to provide alternative arrangements for quickly and uniformly adding various processing fluids to foodstuffs. It is also desirable to provide an arrangement for adding several different processing fluids to a foodstuff in rapid succession.